Airplane



Oct. 4, 1932.

w. B. STOUT W 1,880,997

AIRPLANE Filed March 28, 1930 Q INVENT% Wz'ZZmm' Stout Patented Oct. 4,' 1932 UNITED STATES" PA NT QFFICE WILLIAM n. srou'r, or DETltOIT, MICHIGAN AIRPLANE Application filed March v27a, 1930. Serial No. 439,591.

This invention relates to airplanes, and particularly to the driving means therefor, the principal object "being theprovision of a new and novel and propellers. 1 V

Another object is the provision of means for mounting the engines on an airplane whereby maximum 'eiiiciency may be ohtained with minimum'parasitic resistance.-

1 -Another object is to provide a novel multiple power plant unit for airplanes. Another objectis the provision of an airplane providedwith one or more power plant units, each of which includes a plurality of engines arranged in alignment longitudinally of'the airplane. i i Anothero-bject is to provide a construction as above described in which each of the as above described in which all engines is provided with an independent pro- I peller and in which the pitch of one propeller is greater than that of a propeller rearward thereof. I

Another object is to provide a construction of the power plants are of the tractor'type, that is, in which the propellers are forward of their respective engines, whereby the engines will be cooled by the blast of air from their respective propeller-s whenthe airplane is taxi-ing on the ground. v

I Another object is the provision of construction as above described in which thediameter of any one of such propellersi's larger than that of a propeller rearward thereof and that of a propeller forward smaller than thereof.

Another object is the provision of a power plant unit for airplanes including a plurality of engines mounted in alignment longitudinally of an airplane, each of the engines being provided with an independent propeller and each engine being spacedfrom its next adjacent engine by a distance at least as great as the diameter of the propeller ,driventhereby.

Another objectis to provide a power plant unit for; airplanes including a plurality of, engines mounted in alignment longitudinally of the airplane,

v each rairplane being provided with an independent propeller and arrangement of power plansthe number of blades on said propellers increasing in number from the first one thereof to the last one thereof.

The above being among the objects of the present invent-ion, the same consists incertain'novel features of construction and combination of parts to be hereinafter described with reference to the accompanying drawing, and then claimed, having the above and other objects in View. w v

In the accompanying drawing which shows a suit-able embodiment of the present inventhat the parasitic resistance offered by the engines during. flight is increased directly in'accordance with the number of engines. It has been suggested that two engines be provided in back to back relationship, each driving its'own independent propeller, and with the forward propeller serving as a tractor and the rearward propeller serving as a pusher. However, as far as I am aware, this is as far as the attempts have been carried to reduce the parasitic resistance offered in multiple power plant designs.

A disadvantage of such a construction is that the rear'engine, in being placed for wardly of 'its propeller, is very inefiiciently cooled when the airplane is taXi-ing on the ground, and likewise in the air when the front engine stops, as it receives very little benefit from the air set in motion by its own propeller.

In accordance with the present invention I provide a construction particularly adaptable for large planes, and in which the parasitic resistance set up by the power plants is increased over that of smaller planes but very condition ofthe engines.- 7

V propeller 21,

- g with a propeller 22 and the last engine 20 is provided with are positioned little, if any, due to themultiplicity' 012-1311;; power plants. The essential'feature of the present invention is the arrangement of the,

power plants in alignment longitudinally of the airplane, suitable-fairing being provided between thevarious engines so as to reduce the parasiticiresistance offered by them .to' substantially; no more' tha'n set "up by the first engine, and in so' incorporatingin this assembly of engines certain novel features which-offset the losses which of the aligned would otherwise arise because Referring to the accompanying drawing, I show in a more or less diagrammatic man nor an airplane comprising a fuselage 10,

Wings 1 1, ru'dder 12, stabilizer- 13, landing gear 14 provided with suitable wheels 15, and tail wheel '16. V Asa ingithe princ1pals ,-of the present invention, I show mountedabove the fuselage on suitable struts. 17 three engines 18,719, and 205 Th'evforward engine 18 is provided with a the center engine 19' is provided a propeller 23." v The engines "ment longitudinally of the airplane. V The propeller 21 is 'ofgreater diameter than the propeller 22,] and the propeller .22 iszof:

than the propeller 23.

greater diameter a have shown the forward propeller 21 as having twoblades, the center propeller 22' as having three blades, and the last propeller "as having four blades, but not necessary in ofvthe present-invention. Furthermore, the

, engine 18 is spaced from the engine 19 by a' distance at least as great as, the diameter 21,-and the engine 1s of the propeller.

engine 19 by-a distance at spaced from the least as great ler 22. Furthermore, the pitchof the propeller 23 is greater than thepitch of the propeller 22,- andt-he pitch of the propeller 22 is greater than the pitch of the propeller The forward engine is preferably provided with .a streamlined noseportion 24, and the engines 18 and 19, and 19 and 20 are'connected by preferably cylindrical fairing members 25 and 26 respectivelyof 'substantiallyithe same diameter, as the maximum diameter of r the nose piece 24,, and the engine 20 is pro-- vided with a rearwardly projecting stream- ,lined' tail 27, this reducing the areas of the engines whichare exposed to the flow of air s'o'as to reduceas much as possible the parasitic resistance 'which would otherwi'se be offered by the engines in, direct proportion to their number. Where the engines are of the radialj air-cooled type as shown, their cylindersare preferably permitted to project beyondthese fairing membersin orderto perm t he-ir op r c olins of e am means of illustratwith 1 their axes in alignthis being preferable the broader aspects as the diameter of the'p'ropels,

The reason that I reduce the diameter of I the propellers from the front to rear is that the slip stream from a propeller is known to reduce in diameter rearwardly of the propeller, and accordingly I reduce the'diameter of the following propellers an amount'to insure such propellers working in v, the slip stream from the propeller in advance thereof; Furthermore, it eliminates the tendency of blade which would otherwise occur due to the propeller blades passing intov and out from the propeller in adof the slip stream.

vance thereof. This permits meto design the r pitch ofthe propellers with'certainty, inasmuch as thevelocity of such slip stream can be quite acurately determined; Thisjpermits me to increase the pitch of-the following pro pellers an amount sufficient to overcome the loss that would otherwise occur du to such propellers working in the slipstream of the propeller or propellers, in advance thereof,

and so that I am enabled to insure all of the engines working at spe d-1 c "I prefer to position the engines in the spaced relation described in order to prevent,

the same efficiency and i the turbulence of the air that "mayohe" pres ent immediately behinda propeller from affooting the efliciency of'the'following propel ler, and I preferto increase the number of blades on the propellers, fromfront to rear, to compensate for the loss of-blade area due to reductionin diameter.

While I have shownonly three engines supported in a manner hereinidescribed, it is to be understood that this is merely for the pur-' pose of explanation, and that'this number maybe increased as maybe found necessary or desirable, thesame-proportioning as above described ibeing preferably: carried out 1 throughout allof the engines regardless of the number mountedin alignment; Furthermore, it :is also to be understood that any" number of such'units may be employed on an airplaneasmay be found necessaryor deg sirable, and that as far 7 as the present inven tion is, concerned, whether such engines'are 1 Y mountedeaboveorbelow the wings, or in any other position, is immateriahit being under stood that wherever they are mounted they are preferably positioned sufiiciently outside of the zone of'infiuence ofthe wings upon the air so 7 as [not to interfere with the efficiency of the wings ortheir own efficiency. I 5

1 Eormalchanges may be made in the specific 7 embodiment of the invention described with out-departing from the spirit or substance of the broad. invention, the scope of which is I commensurate with the appended claim. 1

'WhatI claimisr V v. V

. In an airplane engine fna'cell'e' structure threeor more engines disposed intandem, a propeller driven by each engine, the propellers being in alternating relation-with the enir s wer r ell bein d sarm- Vance of its driving engine, the diameter of the rear propellers being such that the tips thereof will revolve in the slip stream of the preceding propellers and the pitch of the rearward propellers being greater than that of the forward propellers, the axial distance between any two propellers being at least equal to the diameter of the foremost of the 32111. 1 lVlLLIAM B. STOUT. 

